Browsers will use heuristic caching, which can be unpredictable. Set explicit cache headers.
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
C
Image Optimization
Action
50 images, 0 KB saveable
REVIEW
50 images, 0 KB saveable
Warning::
!
https://assets.nhle.com/logos/nhl/svg/MIN_light.sv... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://assets.nhle.com/logos/nhl/svg/EDM_light.sv... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://assets.nhle.com/logos/nhl/svg/MTL_light.sv... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://assets.nhle.com/logos/nhl/svg/UTA_light.sv... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://assets.nhle.com/logos/nhl/svg/CAR_light.sv... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://assets.nhle.com/logos/nhl/svg/PHI_light.sv... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://assets.nhle.com/logos/nhl/svg/PIT_light.sv... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://assets.nhle.com/logos/nhl/svg/COL_light.sv... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://assets.nhle.com/logos/nhl/svg/TBL_light.sv... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://assets.nhle.com/logos/nhl/svg/DAL_light.sv... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://assets.nhle.com/logos/nhl/svg/BUF_light.sv... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://assets.nhle.com/logos/nhl/svg/ANA_light.sv... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://assets.nhle.com/logos/nhl/svg/OTT_light.sv... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://assets.nhle.com/logos/nhl/svg/BOS_light.sv... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://assets.nhle.com/logos/nhl/svg/LAK_light.sv... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://assets.nhle.com/logos/nhl/svg/VGK_light.sv... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
50images4.0 MB
0oversized-0 KB
45legacy format
16missing dimensionsCLS risk
Set explicit width and height to prevent CLS.
Why this matters
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Why this matters
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Why this matters
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Why this matters
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Why this matters
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Why this matters
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Why this matters
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Why this matters
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Why this matters
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Why this matters
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Why this matters
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Why this matters
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Why this matters
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Why this matters
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Why this matters
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Why this matters
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
A+
Text Compression
All text resources are compressed
PASS
All text resources are compressed
Info::
✓
All text resources are compressed
All text resources are properly compressed.
A+
Font Loading
2 fonts (94 KB)
PASS
2 fonts (94 KB)
Info::
i
2 font(s) use font-display: swap (FOUT risk but functional)
Web fonts
2
94 KB total
Render-blocking
0
of 2
Dominant font-display
swap
Most common across fonts
Font loading timeline
TransferFOIT (block)FOUT (swap)
UcC73FwrK3iLTeHuS_nVMrM...woff2swap
Size47 KB
Load time50 ms
Start469 ms
RiskFOUT — text flashes from fallback to web font
UcC73FwrK3iLTeHuS_nVMrM...woff2swap
Size47 KB
Load time69 ms
Start905 ms
RiskFOUT — text flashes from fallback to web font
Optimization checklist
Preload critical fonts (priority=high)
Use woff2 format for all fonts
Set font-display to swap, optional, or fallback
Subset large fonts (≤100 KB each)
A+
Resource Caching
All resources properly cached
PASS
All resources properly cached
Info::
✓
No caching issues found
All static resources have appropriate caching headers.
A+
Critical Rendering Path
No render-blocking resources
PASS
No render-blocking resources
Info::
✓
No render-blocking resources detected
A+
Resource Hints
11 hints, 0 missing preconnects
PASS
11 hints, 0 missing preconnects
Info::
✓
Page uses 11 resource hint(s)
Current Resource Hints
preconnect
4
preload
5
dns-prefetch
2
prefetch—
11 resource hints configured
A+
Render-Blocking Resources
No render-blocking resources detected
PASS
No render-blocking resources detected
Info::
✓
No render-blocking resources detected in <head>
A+
Third-Party Resources
No third-party resources detected
PASS
No third-party resources detected
A+
Green Hosting
Whether the site is served from green-energy infrastructure
PASS
Green Hosting
This site is hosted on green energy infrastructure
Provider: Cloudflare
Network Waterfall
108 requests over 2689ms
INFO
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
100%of JavaScript execution is third-party
First-party Third-party7993ms · 1847KB · €128/mo
Script
Category
Execution
Transfer
Unused
Monthly Cost
Verdict
assets.nhle.com
assets.nhle.com
Other
1864ms
919 KB
69%
€30/mo
Costly
www.nhl.com
www.nhl.com
Other
1646ms
39 KB
—
€26/mo
Costly
OneTrust
cdn.cookielaw.org
Consent
989ms
18 KB
—
€16/mo
Essential
Unattributable
Unattributable
Other
875ms
0 KB
—
€14/mo
Costly
OneTrust
cdn.cookielaw.org
Consent
541ms
124 KB
47%
€9/mo
Essential
Google Tag Manager
www.googletagmanager.com
Tag Manager
494ms
164 KB
37%
€8/mo
Costly
www.nhl.com
www.nhl.com
Other
409ms
56 KB
68%
€7/mo
Costly
securepubads.g.doubleclick.net
securepubads.g.doubleclick.net
Other
292ms
188 KB
70%
€5/mo
Costly
public.flourish.studio
public.flourish.studio
Other
248ms
15 KB
—
€4/mo
Costly
www.nhl.com
www.nhl.com
Other
237ms
121 KB
32%
€4/mo
Costly
Google Tag Manager
www.googletagmanager.com
Tag Manager
219ms
161 KB
54%
€4/mo
Costly
securepubads.g.doubleclick.net
securepubads.g.doubleclick.net
Other
102ms
34 KB
—
€2/mo
Optional
OneTrust
cdn.cookielaw.org
Consent
76ms
9 KB
—
€1/mo
Essential
assets.nhle.com
Other
Costly
Execution1864ms
Transfer919 KB
Unused69%
Monthly Cost€30/mo
www.nhl.com
Other
Costly
Execution1646ms
Transfer39 KB
Monthly Cost€26/mo
OneTrust
Consent
Essential
Execution989ms
Transfer18 KB
Monthly Cost€16/mo
Unattributable
Other
Costly
Execution875ms
Transfer0 KB
Monthly Cost€14/mo
OneTrust
Consent
Essential
Execution541ms
Transfer124 KB
Unused47%
Monthly Cost€9/mo
Google Tag Manager
Tag Manager
Costly
Execution494ms
Transfer164 KB
Unused37%
Monthly Cost€8/mo
www.nhl.com
Other
Costly
Execution409ms
Transfer56 KB
Unused68%
Monthly Cost€7/mo
securepubads.g.doubleclick.net
Other
Costly
Execution292ms
Transfer188 KB
Unused70%
Monthly Cost€5/mo
public.flourish.studio
Other
Costly
Execution248ms
Transfer15 KB
Monthly Cost€4/mo
www.nhl.com
Other
Costly
Execution237ms
Transfer121 KB
Unused32%
Monthly Cost€4/mo
Google Tag Manager
Tag Manager
Costly
Execution219ms
Transfer161 KB
Unused54%
Monthly Cost€4/mo
securepubads.g.doubleclick.net
Other
Optional
Execution102ms
Transfer34 KB
Monthly Cost€2/mo
OneTrust
Consent
Essential
Execution76ms
Transfer9 KB
Monthly Cost€1/mo
These scripts may cost more than they're worth
assets.nhle.com adds 1864ms and costs ~€30/month
www.nhl.com adds 1646ms and costs ~€26/month
Unattributable adds 875ms and costs ~€14/month
Google Tag Manager adds 494ms and costs ~€8/month
www.nhl.com adds 409ms and costs ~€7/month
securepubads.g.doubleclick.net adds 292ms and costs ~€5/month
public.flourish.studio adds 248ms and costs ~€4/month
www.nhl.com adds 237ms and costs ~€4/month
Google Tag Manager adds 219ms and costs ~€4/month
100% of JavaScript execution time is spent on third-party scripts. Consider auditing which scripts are essential.
Why this matters
When third-party JS execution time exceeds your own, performance gains from frontend work are capped by code you don't own.
Learn more ▾▴
Every millisecond of third-party JS competes with your own for main-thread time. If their share is bigger than yours, optimization on your code base barely moves the needle. Audit, defer, or remove third-parties before further frontend optimization. Use Lighthouse's third-party audit to identify the worst offenders.
Source: web.dev
assets.nhle.com takes 1864ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
Why this matters
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
69% of assets.nhle.com's code is unused. The script may be loading features you don't use.
Why this matters
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
www.nhl.com takes 1646ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
Why this matters
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
Unattributable takes 875ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
Why this matters
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
Google Tag Manager takes 494ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
Why this matters
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
www.nhl.com takes 409ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
Why this matters
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
68% of www.nhl.com's code is unused. The script may be loading features you don't use.
Why this matters
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
securepubads.g.doubleclick.net takes 292ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
Why this matters
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
70% of securepubads.g.doubleclick.net's code is unused. The script may be loading features you don't use.
Why this matters
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
public.flourish.studio takes 248ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
Why this matters
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
www.nhl.com takes 237ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
Why this matters
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
Google Tag Manager takes 219ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
Why this matters
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
54% of Google Tag Manager's code is unused. The script may be loading features you don't use.
Why this matters
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.